1980 Kenworth W900A light rebuild thread

This is the one in the ‘81. They had 2 different hvac suppliers back then. RedDot and Evans. I believe this style is RedDot.

 

I lowered the ones down on the ‘81 by welding on extensions and drilling holes in them to bolt to original place. Lowered original bottom step down 3-1/2”

 

Unfortunately. This is the only pic I have of the steel handle after I reassembled everything.

 

Maybe u can educate me. Im to young to have seen 3 brake valves on the dash, and always wondered what the blue one was for? I see it alot in the older trucks maybe up until the mid 80s or so

 

It was called a “bus” valve. It was mandated for the new “121” brake rule in the mid 70’s. It is just an extra valve usually plumbed to an isolated tank that is tractor only to allow just enough air to release the cans so the truck can move to safety after a total air loss failure. They were originally mandated on air braked school and passenger busses in california as far back as the 50’s.
The extra tanks that Pete mounts under the cab door were originally installed for that valve only. Now they are used for other things. That system was a pita and no one understood it so it went away by 83-84 time frame.

 

Far as I can remember mine just had the standard 3 tanks.